Calculating Calcium: Georgia Onions Could Benefit From Additional Application

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By Clint Thompson

Georgia’s onion crop can benefit from additional calcium applications. That’s the messaged relayed by Tim Coolong, associate professor in the University of Georgia College of Agricultural and Environmental Sciences.

Coolong presented information during a recent UGA Extension Vidalia Onion meeting. Since Georgia’s onion crop is grown on sandy soils, calcium can be at lower levels than they need to be. Additional applications can help the crop’s firmness and quality going into storage.

“The type of onions that we grow here in Georgia, the short-day onions, they tend to have thinner cell walls actually compared to a long-day storage onion that you might grow up in New York or Michigan or somewhere like that. The idea would be that by adding additional calcium you can fortify the cell wall, which would help enhance storage,” Coolong said.

“On some of our ground, if we’re below 1,000 pounds per acre of calcium, typically in the 700 pounds per acre range, doing some supplemental calcium during the season can help. We did find that once you did get above 1,000 to 1,100 pounds per acre of calcium that we don’t see as much of an effect.”

Coolong did say that since some Georgia fields are rotated among other crops, like peanuts. Growers apply gypsum which contains calcium. Those soils should already be above the 1,000-pound range.